Railway traffic controlling apparatus



g- 1941- J. M. PELIKAN 2,251,689

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Nov. 27, 1940 N N Q r lwr N a@ QIj QU J k k INVENTOR q JoimM Pelikan 4 HIS ATTORNEY Patented Aug. 5, 1941 RAILWAY TRAFFIC CONTROLLING APPARATUS John M. Pelikan, Pittsburgh, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application November 2'7, 1940, Serial No. 367,352

7 Claims.

My invention relates to railway trafiic controlling apparatus and more particularly to a manual block system employing reversible track circuits in which all of the control operations are performed by means of track circuits without the necessity for any control line wires. My invention is, accordingly, well adapted to a system of A. P. B. signaling where the use of control line wire is undesirable or impractical.

One object of my invention is to provide a block system for two-direction signaling on a single track without employing control line wires. Another object of my invention is to provide a comparatively simple system of the above character which provides broken-down rail joint protection and in which traffic cannot be falsely set up in both directions at the same time by stray currents. Other objects, purposes and features of my invention will be apparent from the description which follows. I g

I accomplish the foregoing objects by providing each track circuit with two polarized track relays, one at each end of the associated track circuit,

each of these relays being so connected and arranged that it is operated as a track relay for one direction of trafiic and as a floater relay for the other direction of traffic. I establish traflic direction in accordance with the polarity of the track current, the apparatus being so arranged that current of a given polarity clears the westbound headblock signal while preventing the clearing of the eastbound signal, whereas current of the reverse polarity clears the eastbound headblock signal and at the same time prevents clearing of the opposing or westbound headblock signal.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing a stretch of a single track railroad equipped with apparatus embodying my invention.

Referring to the drawing, the block D G between the two passing sidings is divided by means of insulated rail joints 2 at locations D, E, F, and G into a plurality of track circuit sections of which three sections ITR, 2TB, and 3TB. are shown in the drawing. Eastbound.- trafiic entering the block is governed by the signal Sl which may be of anysuitable type but which is shown diagrammatically as having an operating winding 3 and a rotor 4. This signal is controlled froma suitable source of current which is not shown but which has the terminals 13-0,

i position R in which certain contacts, designated on the drawing as N and R within a circle, are respectively closed. That is to say, with lever LI in the normal position, as shown, contacts N will be closed so that relay IETR. is then connected with the track, Whereas contacts R will be open, so that. the battery TB will be disconnected. In order that a traffic move may be established through the .block, cooperation is required between the levers LI and L2 at the two ends, so that if lever Ll is moved to the normal position (for an eastbound traific move) lever L2 must likewise be placed in its normal position, as shown. When so placed, the contacts N of lever L2 will be closed so that track current of normal polarity will then be supplied from the battery TB to the rails of section 3TR, thereby energizing the eastbound track relay BETR which closes its normal contacts 9 and I0, and polar contacts H and I2. The westbound track relay 3WTR will be disconnected at contacts R of lever L2 so that signal S2 will be deenergized at contacts 1 and 8 and will be at stop to hold any approaching westbound traffic until the eastbound train has fully cleared the block DG.

Assuming that levers LI and L2 both occupy the normal position, as shown, whereupon relay 3EI'R is energized with current of normal polarity and all of its contacts are closed, this will connect the track battery 'I'B over an obvious circult which includes contacts 9 to I2, inclusive, of relay 3ETR across the rails of section ZTR, thereby energizing the eastbound track relay ZETR. This track current will be of normal polarity so that all of the contacts l3, l4, l5, and N5 of relay ZETR. will be closed. However, the polar contacts I1 and I8 of relay 2WTR will be open since these contacts close only when current of reverse relative polarity is supplied to relayl 2WTR. For obtaining broken-down rail joint protection, it will be desirable to stagger the current polarity in adjoining track circuits, so that if current of normal polarity'is supplied to .section 3TB, the current which is relayed by relay 3ETR into section 2TH should be of reverse polarity and the terminals of relay ZWIR should be so connected to the track that polar contacts I! and 18 will then be open.

Continuing the foregoing explanation as to how current is relayed from the most remote section of the block through the successive sections until the entering section is reached, energization of relay ZETR causes current of normal polarity to be supplied from battery TB to the section ITR over the contacts 13 to 16, inclusive, of relay ZETR and causes the energization of relay IE'I'R which then clears the entering signal SI to permit eastbound traffic to enter the block.

Summarizing the above operations, it will be seen that when levers LI and L2 are both placed in the normal position, the track circuits 3TB, 2TB, and for the purpose of energizing the eastbound track relays and particularly relay IETR for the entering section which then clears the headblock signal. An identical sequence of operations takes place when the levers LI and L2 are both placed in the reverse position, current of reverse polarity being then supplied progressively to sections ITR, ZTR', and 3TH so that the westbound track relays' IW'I'R, ZWTR, and 3WTR. become progressively energized. The opposing or eastbound signal SI will then be at stop and the entering or westbound signal S2 will indicate proceed. The detailed operation for a westbound move need not be described in detail as it will be adequately clear from the previous description for an eastbound move.

With trafiic direction established for an eastbound move and signal SI at proceed, the passage of the train will progressively deenergize the track relays IETR, ZETR, and 3ETR, thus maintaining signal SI at stop until the train fully clears the block DG. This is so because the release of relay IETR opens the signal operating circuit at contact 5; the release of relay ZETR deenergizes the section ITR, thus keeping relay IETR released; and th release of relay 3ETR deenergizes section 2TH, and so maintains section ITR deenergized.

It will be noted that with eastbound traflic conditions established, the westbound relays IW'IR and ZWTR at the intermediate locations ITR. become successively energized.

E and F will be energized (although the current will be of the wrong polarity) so that their normal contacts will be closed. Track battery current will not, however, be fed back into the entering ends of sections 2TB. and 3TB. because polar contacts l9 and 20, and I! and I8 will be open. Thus, relays IWTR and 2WTR are merely floater relays when traflic is eastbound. Similiarly, relays ZETR and 3E'I'R are floater relays for a westbound trafiic move.

Following an eastbound traffic move, if it is desired to establish westbound trafiic direction, lever L2 should preferably be moved to its reverse position before lever Ll is reversed in order first to reverse relay 3ETR which deenergizes relays ZETR and IETR before the closing of contacts R of lever LI superimposes reverse energy on section ITR. That is to say, when reversing the established traffic direction, the lever at the leaving end of the block (for the traffic direction thenexisting) should preferably be reversed before the reversal of the lever at the entering end. However, no unsafe operation can result from a lever reversal in the opposite order because the track circuits cannot be properly energized for the new direction until the distant lever for that direction is reversed, whether this reversal oocurs before or after the operation of the other lever.

Should it be desired to provide automatic train control within the block D-G, this can be done by replacing the track batteries TB with code transmitters so that code will be received by the train as soon as it passes the headblock signal and each phantom signal location such as E and F, and will continue to be received throughout each section until the train passes out of the block. Also, intermediate two-position wayside signals controlled by the respective track relays can obviously be added at the locations E and F. If code is used, the signals can be of the threeposition type by employing steady or uncoded energy for the caution position and code for the proceed position. Furthermore, if a coded line circuit is unobjectionable, then centralized traffic control can be incorporated for manually controlling the levers LI and L2 by code impulses from a central office location. Obviously, in the latter case, the levers can be replaced by suitable relays having the necessary contact equipment.

From the foregoing description, it will be apparent that I have provided a comparatively simple A. P. B. system which does not require any control line wires and in which traffic cannot be falsely set up in both directions at the same time. Before an entering signal can be cleared, the trafiic levers at both ends of the block must correspond in position. By placing the levers in correspondence, the track circuits are progressively relayed from the distant end to the entering end of the block, first setting the opposing headblock signal at stop, then checking the unoccupancy of each track circuit, in turn, and finally clearing the entering headblock signal. If a cross or an open occurs, only one trafiic direction can be established until the failure is remedied but no unsafe operation can result from such failure.

Although I have herein shown and described only one form of railway trafiic controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a stretch of track over which trafiic may move in either direction, said stretch being divided into a plurality of track circuit sections, a first and a second manually controlled lever at the first and the second end respectively of said stretch, said levers having a normal and a reverse position, a first and a second headblock signal also at the respective ends of said stretch, an eastbound and a westbound polarized track relay for each of said track circuit sections, all of said track relays except the first eastbound relay and the first westbound relay being permanently connected across the rails of the respective track section, means effective when said first lever is moved to its normal position for connecting said first eastbound relay across the rails of the first eastbound section, means effective when said second lever is moved away from its reverse position for setting said second headblock signal at stop, means effective when said second lever is moved to its normal position for supplying current of positive polarity to the rails of the last eastbound section to thereby energize the eastbound track relay for that section so as to cause polarized response thereof,

means'contr'olled by said last named track relay for'supplying track circuit current of properpolarity to the rails of the adjoining section to energize the eastbound track, relay of said adjoining section and so to relay current of proper polarity to the rails of the next adjoining section and in turn to the rails of said first eastbound section for providing polarized response of said first eastbound relay, and means controlled by said first eastbound relay for clearing said first headblock signal.

2. In combination with a stretch of track over which traffic may move in either direction, said stretch being divided into a plurality of track circuit sections, a first and a second manually controlled lever at the first and second end respectively of said stretch, said levers having a normal and a reverse position, a first and a second headblock signal also at the respective ends of said stretch, an eastbound polarized track circuit for each of said sections including an eastbound polarized track relay, a westbound polarized track circuit for each of said sections including a westbound polarized track relay, the rails of each of said sections being common to said eastbound and said westbound track circuits and the polarity of track circuit current being opposite in any of said sections according as eastbound or westbound tramc is passing therethrcugh, means effective when said second lever is moved to its normal position for setting said second headblock signal to stop and for energizing said eastbound track circuits progressively from said second to said first headblock signal location, and means effective when said first lever is moved to its normal position for clearing said first headblock signal.

3. In combination with a stretch of track over which trafiic may move in either direction, said stretch being divided into a plurality of track circuit sections, a first and a second manually controlled lever at the first and second end respectively of said stretch, said levers having a normal and a reverse position, a first and a second headblock signal also at the respective ends of said stretch, an eastbound polarized track circuit for each of said sections including an eastbound polarized track relay, a westbound polarized track circuit for each of said sections including a westbound polarized track relay, the rails of each of said sections being common to said eastbound and said westbound track circuits and the polarity of track circuit current being opposite in any of said sections according as eastbound or westbound trafilc is passing therethrough, means effective when said second lever is moved to its normal position for setting said second headblock signal to stop and for energizing said eastbound track circuits progressively from said second to said first headblock signal location, means effective when said first lever is moved to its normal position for clearing said first headblock signal, means effective when said first lever is moved to its reverse position for setting said first headblock signal to stop and for energizing the westbound track circuits of said stretch progressively from said first to said second headblock signal location, and means effective when said second lever is moved to its reverse position for clearing said second headblock signal.

4. In combination with a stretch of track over which trafiic may move in either direction, said stretch being divided into a plurality of track circuit sections, a first and a second manually controlled lever at the first and second end respec- 'tivel y'of lsaid stretch, said levers having a normal and a reverse position,-a first and a second headblock signal also at the respective ends of said stretch, an eastbound polarized track circuit for each 10f said sections including an eastbound polarized track relay, a Westbound polarized track circuit for each of said sections including a westbound polarized track relay, the rails of each of said sections being common to said eastbound and said westbound track circuits and the polarity of track circuit current being opposite in any of said sections according as eastbound or westbound traffic is passing therethrough, means effective when said second lever is moved to its normal position for setting said second headblock 'signalto stop and for energizing said eastbound track circuitsiprogressively from said second to said first headblock signal'location, means effective when said first leveriis' moved to its normal position for clearing said first headblock signal, and for preventing the energization of said westbound .track circuits, means effective when said first leveris moved to, its reverse position for setting said, first headblock signal to stop and for energizing said westbound track circuits progressively from said first to said second headblock signal location, and means effective when said second lever is moved to its reverse position for clearing said second headblock signal and for preventing the energization of said eastbound track circuits.

5. In combination with a stretch of track over which trafiic may move in either direction, said stretch being divided into a plurality of track circuit sections, a first and a second source of track circuit current at the respective ends of said stretch, an eastbound track relay at one end and a Westbound track relay at the other end of said stretch, a westbound track relay connected across the rails of the first track circuit section at said one end, an eastbound track relay connected across the rails of the last track circuit section at said other end, all of the aforesaid track relays being polarized, the eastbound and westbound track relays associated with any given section being oppositely polarized so that track circuit current of given polarity will operate one but not the other relay, manually controllable means at said other end efiective when occupying a first position for connecting said second source across the rails of said last section to thereby operate the eastbound track relay for said last section, other manually controllable means at said one end also efiective when occupying a first position for connecting the eastbound track relay at said one end across the rails of said first section, means controlled by the eastbound track relay for said last section for relaying track circuit current to the rails of said first section to thereby operate the associated eastbound track relay, and means efiective when both said manually controllable means are occupying a second position for disconnecting the track circuit source from said last section and the eastbound track relay from said first section and for connecting said first source across the rails of said first section and said first-mentioned westbound relay across the rails of said last section, to thereby operate said westbound relay for the first section and to relay track circuit current to said last section so as to operate the westbound track relay associated therewith.

6. In combination with a stretch of track over which traffic may move in either direction, said stretch being divided into a plurality of track circuit sections, a first and a second source of track circuit current at the respective ends of said stretch, an eastbound track relay at one end and a westbound track relay at the other end of said stretch, a westbound track relay connected across the rails of the first track circuit section at said one end, an eastbound track relay connected across the rails of the last track circuit section at said other end, all of the aforesaid track relays being polarized, the eastbound and westbound track relays associated with any given section being oppositely polarized so that track circuit current of given polarity will operate one but not the other relay, means efiective when trafiic is set up in a given direction over said stretch for connecting said second source across the rails of said last section to thereby operate the last eastbound track relay and for connecting the first eastbound track relay across the rails of said first section, means including a polar contact of said last eastbound relay for relaying track circuit current to said first section to thereby operate said first eastbound relay, and means effective when traffic is set up in the reverse direction for connecting said first source across said first section to operate the last westbound track relay and connecting the first westbound track relay across the rails of said last section, track circuit current being relayed to said last section over a polar contact of said last westbound track relay to thereby operate said first westbound track relay.

7. In combination with a stretch of track over which traific may move in either direction, an eastbound track circuit for said stretch controlled by current of given polarity, an eastbound polarized track relay connected across the rails of said track circuit when and only when eastbound trafiic direction is established over said stretch, said eastbound relay being responsive to current of said given polarity, a westbound polarized track relay permanently connected across the rails of said track circuit and responsive to current of the reverse polarity, and means effective when westbound trafiic direction is established over said stretch for supplying current of said reverse polarity to the rails of said track circuit to thereby cause polarized response of said westbound track relay.

JOHN M. PELIKAN. 

